Semiconductor device and method of manufacturing the same

Abstract

To provide a semiconductor device in which the deterioration of the rewrite property is suppressed. In a memory cell region, magnetoresistive elements in a semiconductor magnetic-storage device are formed in an array shape in a mode that the magnetoresistive elements are arranged at portions where digit lines extending in one direction intersect bit lines extending in the direction approximately orthogonal to the digit lines. The digit line and the bit line have such a wiring structure constituted by covering a copper film to be a wiring main body with a cladding layer. One end side of the magnetoresistive element is electrically coupled to the bit line via a top via formed from a non-magnetic material.

1 . A semiconductor device comprising:
 a first region formed in a main surface of a semiconductor substrate;   a magnetoresistive element formed in the first region;   a first wiring main body formed so as to extend in a first direction directly under the magnetoresistive element with some spacing;   a second wiring main body formed so as to extend in a second direction intersecting the first direction directly on the magnetoresistive element with some spacing;   a first conductor portion that is formed between the magnetoresistive element and the second wiring main body and electrically couples the magnetoresistive element and the second wiring main body; and   a magnetic field-shielding layer that is formed in a prescribed position relative to the magnetoresistive element and shields a magnetic field generated by a current flowing through the first wiring main body and the second wiring main body,   wherein the first conductor portion is formed from a non-magnetic material, and the magnetic field-shielding layer is formed over the surface of the second wiring main body in a mode that excludes a portion of the second wiring main body facing the magnetoresistive element and the first conductor portion.   
     
     
         2 . The semiconductor device according to  claim 1  comprising:
 a second region that is formed in the main surface of the semiconductor substrate, in which the second wiring main body extends; 
 a third wiring main body that is formed below the second wiring main body with some spacing in the second region; and 
 a second conductor portion that is formed between the third wiring main body and a portion of the second wiring main body lying in the second region and electrically couples the third wiring main body and the second wiring main body. 
 
     
     
         3 . The semiconductor device according to  claim 2 ,
 wherein the magnetic field-shielding layer is furthermore formed over the surface of the second conductor portion.   
     
     
         4 . The semiconductor device according to  claim 2 ,
 wherein the magnetic field-shielding layer is formed over the surface of the second wiring main body in a mode that excludes the second conductor portion.   
     
     
         5 . The semiconductor device according to  claim 1 ,
 wherein the magnetic field-shielding layer is formed from a soft magnetic material.   
     
     
         6 . A method of manufacturing a semiconductor device having a first region and a second region in a main surface of a semiconductor substrate comprising the steps of:
 forming a first insulating film over the main surface of the semiconductor substrate;   forming a first wiring trench extending in a first direction in the first insulating film;   forming a first wiring main body in the first wiring trench;   forming a second insulating film over the first insulating film so as to cover the first wiring main body;   forming a magnetoresistive element over the surface of the second insulating film;   forming a third insulating film over the second insulating film so as to cover the magnetoresistive element;   forming a first opening to expose the magnetoresistive element in the third insulating film;   forming a first electroconductive film constituted by a non-magnetic material over the third insulating film so as to fill up the first opening;   removing a portion of the first electroconductive film lying over the upper surface of the third insulating film to form a first conductor portion electrically coupled to the magnetoresistive element by a portion of the first electroconductive film left in the first opening;   forming a fourth insulating film over the third insulating film so as to cover the first conductor portion;   forming a second wiring trench extending in a second direction intersecting the first direction in the fourth insulating film so that the first conductor portion is exposed at the bottom surface;   forming a magnetic field-shielding layer that shields a magnetic field over the side wall of the second wiring trench in a mode that excludes the bottom surface of the second wiring trench; and   forming a second wiring main body electrically coupled to the magnetoresistive element via the first conductor portion in the second wiring trench.   
     
     
         7 . The method of manufacturing a semiconductor device according to  claim 6  comprising the steps of:
 forming a third wiring trench in a portion of the first insulating film lying in the second region; 
 forming a third wiring main body in the third wiring trench; and 
 forming a second conductor portion that passes through the second insulating film and the third insulating film to electrically couple the third wiring main body and a portion of the first wiring main body lying in the second region. 
 
     
     
         8 . The method of manufacturing a semiconductor device according to  claim 7 ,
 wherein the step of forming the second conductor portion includes the steps of:   forming, after the formation of the fourth insulating film and prior to the formation of the second wiring trench, a second opening that passes through the second insulating film, the third insulating film and the fourth insulating film to expose the third wiring main body in the second region;   forming the second wiring trench in the fourth insulating film so as to expose the second opening at the bottom surface;   forming a layer to be a magnetic field-shielding layer so as to cover the bottom surface and the side surface of the second wiring trench, and the side wall of the second opening;   subjecting the whole surface of the layer to be the magnetic field-shielding layer to etching to remove a portion lying at the bottom surface of the second wiring trench, while leaving a portion lying over the side wall of the second wiring trench and a portion lying over the side wall of the second opening; and   forming a portion of a layer to be the magnetic field-shielding layer and a portion of the second electroconductive film each lying in the second opening as the second conductor portion, by filling up the second opening with the second electroconductive film to be the second wiring main body when forming the second wiring main body.   
     
     
         9 . The method of manufacturing a semiconductor device according to  claim 7 ,
 wherein the step of forming the second conductor portion includes the steps of:   forming, after the formation of the third insulating film, a second opening that passes through the third insulating film and the second insulating film to expose the third wiring main body;   forming a third electroconductive film over the third insulating film so as to fill up the second opening; and   removing a portion of the third electroconductive film lying over the upper surface of the third insulating film to form a portion of the third electroconductive film left in the second opening as the second conductor portion.   
     
     
         10 . The method of manufacturing a semiconductor device according to  claim 7 ,
 wherein the step of forming the second conductor portion includes the steps of:   forming, after the formation of the third insulating film, a second opening that passes through the third insulating film and the second insulating film to expose the third wiring main body;   forming a layer to be a magnetic field-shielding layer over the third insulating film so as to cover the side wall of the second opening;   removing a portion of the layer to be the magnetic field-shielding layer lying over the upper surface of the third insulating film, while leaving a portion of the layer to be the magnetic field-shielding layer lying over the side wall of the second opening;   forming a fourth electroconductive film over the third insulating film so as to fill up the second opening; and   removing a portion of the fourth electroconductive film lying over the upper surface of the third insulating film to form a portion of the layer to be the magnetic field-shielding layer and a portion of the fourth electroconductive film each left in the second opening as the second conductor portion.